Flat-knitting machine for alternately producing double welts or rib welts

ABSTRACT

THE MACHINE NEEDLE BAR IS CONNECTED TO ITS DRIVE MECHANISM BY A CONNECTION WHICH CAN BE RIGID TO TRANSMIT KNITTING MOVEMENT FROM THE DRIVE MECHANISM TO THE NEEDLE BAR OF WHICH CAN BE RESILIENTLY YIELDABLE TO EXERT A DRAW OFF FORCE ON THE MACHINE NEEDLE BAR WHILE A WELT IS BEING PRODUCED. THE CONNECTION MAY INCLUDE A COUPLING ARM HAVING TWO TELESCOPIC PARTS PRESSED TOWARD A SHORTENED RELATIONSHIP BY A COMPRESSION SPRING AND WHICH PARTS CAN BE RIGIDLY CONNECTED TOGETHER BY LATCHING A CONTROL ROD. ALTERNATIVELY, TENSION SPRINGS CAN CONNECT THE MACHINE NEEDLE BAR AND ITS DRIVE MECHANISM TO EXERT A RESILIENT DRAW OFF FORCE DURING WELT PRODUCTION, BUT A COUPLING ARM CAN BE CONNECTED BETWEEN THE NEEDLE BAR AND ITS DRIVE MECHANISM TO PROVIDE A RIGID CONNECTION WHEN IT IS DESIRED TO DRIVE THE NEEDLE BAR POSITIVELY TO EFFECT KNITTING MOVEMENTS. A WELT BAR OR A WELT ROD CAN BE USED IN ADDITION TO THE MACHINE NEEDLES TO PROVIDE FURTHER DRAW OFF FORCE.

WE OR LTS Filed April 9, 1969 6 Sheets-Sheet l 1LT 51$ '5 IF 1 s pp 3,614, FLAT-KNITTING MA NE ALTERNATELY PRODUCING DOU RIB WE IN V EN TOR. HA/VSJOACH/M .UPPE

ATMR/YEV Oct. 26, 1971 SUPPE 3,1, FLAT-KNITTING MACHINE FOR ALTERNATELY PRODUCING DOUBLE WELIS 0R RIB WELTS 1 Filed April 9, 1969 6 Sheets-Sheet 2 as 3 a; 37 360 730 797 INVENTOR.

H/i/VQJOALW/M .S'UPPE ArmP/VEY Uct, 2S, 19TH H supp 3514,8WW

FLAT-KNITTING MACHINEFOR ALTERNATELY PRODUCING DOUBLE WEL'IS OR RIB WELIS Filed April 9, 1969 6 Sheets-Sheet 3 132 m we 33 40 43 49 l N V EN TOR. f/AMS'JOJ CH/M SUPPE 147 TOR/YE) H.SUPPE FLAT-KNITTING CHINE FOR ALT LY PRODUCING DO E WELTS OR R TS Filed April 9, 1969 6 Sheets-Sheet 4 INVENTOR. HAM'JO/l CH/M .SUPPE w H. SUPPE FLAT-KNITTING MACHINE FOR ALTERNATELY PRODUCING DOUBLE WELTS 0R RIB WELTS Filed April 9. 1969 6 Sheets-Sheet 5 m r13 r02 101 n ATTORNEY Ufifi. 2S, SUPPE I? FLAT-KNITTING MACHINE FOR ALTERNATELY PRODUCING DOUBLE WELTS QR RIB WELTS Filed April -9, 1969 6 Sheets-Sheet 6 ATTORNEY FLAT-KNITTING MACHINE FOR ALTERNATELY PRODUCING DOUBLE WELTS R RIB WELTS Hansjoachim Suppe, Ingolstadt, Germany, assignor to Schubert & Salzer Maschinenfabrik Aktiengesellschaft,

llngolstadt, Germany Filed Apr. 9, 1969, Ser. No. 815,533 Claims priority, application Germany, Apr. 9, 1968, P 17 60 141.1 Int. Cl. D04b 1/04 US. CI. 66-88 17 Claims ABSTRACT OF THE DISCLOSURE The machine needle bar is connected to its drive mechanism by a connection which can be rigid to transmit knitting movement from the drive mechanism to the needle bar or which can be resiliently yieldable to exert a draw off force on the machine needle bar while a welt is being produced. The connection may include a coupling arm having two telescopic parts pressed toward a shortened relationship by a compression spring and which parts can be rigidly connected together by latching a control rod. Alternatively, tension springs can connect the machine needle bar and its drive mechanism to exert a resilient draw oif force during welt production, but a coupling arm can be connected between the needle bar and its drive mechanism to provide a rigid connection when it is desired to drive the needle bar positively to effect knitting movements. A welt bar or a welt rod can be used in addition to the machine needles to provide further draw off force.

The present invention is used in the production of welts on knitting machines and more particularly in their production on knitting machines with frame and machine needles fixed in two needle bars, the usual rigid connection between the machine needle bar and the drive mechanism being capable of being released so that the machine needles can be used for holding the initial course during the knitting of the welt.

The production of a welt on straight bar knitting machines with two needle bars is normally carried out while only knitting with the frame needle bar, the machine needle bar having been stopped after the formation of the initial course so that the latter can be held by the machine knitting bar. After a suitable number of courses has been produced the machine and frame needle bars cooperate together in closing the welt and then produce rib material. During its production the welt is not subjected to any draw off force.

In order to subject articles with a welt to a direct draw oif force the proposal has been made, see German specification 1,221,757, to connect a welt bar with a course of loops on the frame needles after half the number of courses necessary for the welt has been knitted. However, with this method the first half of the welt is not subjected to draw off tension and the mesh produced tends to be uneven. Furthermore operation of the machine may be obstructed if the knitted courses are not moved clear of the knitting elements, owing to there being no draw oif.

The German specification 1,165,194, see FIG. 16, shows the tensioning of a welt during the whole of the time in which it is knitted on a straight bar knitting machine with two needle bars, is known. In this method the Jersey welt is drawn along the machine needles by fittings provided with welt hooks and drawn off while the frame needles are knitting the welt. For closing the welt, the welt or draw 01f hooks must be moved back along the machine needles towards the frame needles. The movements which have to be performed by the draw oif hooks, which after the com- 3,614,879 Patented Oct. 26, 1971 pletion of the welt have to be moved in a conventional draw off direction, is extremely complicated and elaborate means have to be used for producing them. Moreover, during the transfer procedure no tension is therefore exerted so that the fabric is produced with faults. Moreover the size of the welt is limited to the length in the wale direction of a direct line between frame needles and the shafts of the machine needles. Such welts which are extremely short in the wale direction, though they may be acceptable in some cases since may only be used as lost welts for drawing off rib material, are not suitable as parts of finished articles or parts of articles, more particularly those in Jersey stitch with which there is the requirement of producing a permanent Welt of any desirable length in the wale direction.

One object of the present invention is to provide an improved mechanism, of simple construction, for straight bar knitting machines with two needle bars so as to make it possible to produce welts or rib borders at will, such borders or welts being followed either by rig fabric or plain fabric.

A further object of the invention is to provide such a mechanism which can produce rib borders and welts in any convenient length.

The present invention consists in a mechanism which is adapted for producing welts on a straight bar knitting machine equipped with frame and machine needle bars and with means for causing the bars to perform knitting movements, comprising means for producing a steady draw off force, and means for selectively connecting the machine needle bar with draw off force-producing means or with the means for causing it to perform knitting movements. In this manner the machine needle bar can be used as a welt bar both for drawing oif and for transfer of the stitches.

Preferably the knock over bar of the machine needles is mounted so that it can be brought out of and into its working position in accordance with whether the machine needle bar is connected with the draw off force-producing means or with the means for causing it to perform knitting movements.

In accordance with a preferred embodiment of the invention, the force producing means comprises a resilient means with activating or coupling means for linking the resilient means with the machine needle bar. The resilient means can conveniently be arranged in a coupling arm used for moving the machine needle bar. The resilient means can also, however, be arranged to oppose relative pivoting movement between two levers about a common axis, the two levers forming part of drive means for the machine needle bar. These two levers can be locked by means of a coupling, such as an electromagnetic coupling, to prevent them from swinging, which swinging would otherwise be permitted by the resilient means. In order to limit the draw off travel of the machine needle bar it is possible to provide an adjustable abutment. In order to provide for a rapid replacement of the needle bar, for example when it is desired to change the pattern using different needle set outs, coupling arms can be provided which can be swung so as to release the machine needle bar.

In accordance with a further preferred feature of the invention, sliding or guide ways or guides are provided for the machine needle bar and, again preferably, these guides are rigidly fixed in the frame of the knitting machine.

In order to facilitate movement in the guides of parts such as the machine needle bar and the knock over bar, the latter can be provided with pins journalled in ball bearings.

The invention is now described with reference to the accompanying drawings which show specific embodiments of it.

FIG. 1 shows a mechanism in accordance with the invention on a straight bar knitting machine with bearded needles in transverse section.

FIG. 2 shows a further form of mechanism in accordance with the invention.

FIGS. 3 and 4 show further embodiments of the invention on straight bar knitting machines in which the machine needle bars are fitted with latch needles.

FIG. 5 shows the arrangement of machine needle bar cams and with cams for operating the knock over bar in plan view.

FIG. 6 is a perspective view of parts of the mechanism shown in FIG. 1.

FIGS. 7 to 9 are diagrams of the frame and machine needle bars with various needle set outs.

Before embarking on a specific description of the embodiments of the invention shown in the drawings, it should be mentioned by way of introduction that in order to obtain an even mesh all over the welt, the welt material must be tensioned during the whole of the time in which it is being knitted. In the case of straight bar knitting machines with a single needle bar the sinker loops of the initial course are held by the welt bar, continuously subjected to draw off tension, and after knitting a certain number of courses a welt rod is placed in position for further draw off and the initial course is transferred to the frame needles. The transfer of the initial course is usually carried out by swinging the welt bar over the frame needles, a special form of welt needle being necessary. This form of needle cannot, however, be used for stitch formation, that is to say for knitting.

In the case of prior art straight bar knitting machines with two needle bars application of tension to the welt material during the knitting of the first half of it is not possible since the machine needle bar which holds the first course of the welt fabric is moved out of the way of knitting operations taking place on the frame needles as soon as the initial course has been formed. The machine needle bar then remains stationary. A tensioning and draw off using a welt bar is only possible in the knitting of the second half of the welt fabric.

For the production of fully fashioned pieces of material either with a welt or with a rib border it has been necessary to knit on different straight bar knitting machines equipped either with a welting mechanism or with a ribbing mechanism comprising a second needle bar. Although it was in theory possible to use a 1:1 rib straight bar knitting machine to produce a welt, the quality did not in practice meet the requirement arising in the ease of finished articles or parts of articles ready to be sewn together. The space available in a straight bar knitting machine does not allow the use of both a conventional welting mechanism and also a rib border mechanism in the form of a machine needle bar. In order to provide the possibility of producing both welt and also rib border using a single straight bar knitting machine, the machine needle bar in the embodiments of the invention described is so constructed, and provided with such a driving mechanism, that it can be used for producing both rib border and also welt in a satisfactory manner. The machine needle bar can be equipped with bearded needles, latch needles, pipe needles, or compound needles.

FIG. 1 is a transverse section through a straight bar knitting machine with two needle bars 3 and 4, a sinker bar 41 and a head piece 1 as will be familiar to those skilled in the art. Only those parts of the knitting machine which are necessary for understanding the invention are shown. The machine needles 35 are in the form of bearded needles and cooperate in a conventional manner with the frame needles 40, the sinkers 42, and the knock over bits 43 in knitting 1:1 rib material. The drive mechanism for the frame needle bar 4 is therefore not shown. The

machine needle bar 3 is caused to move horizontally by means of cams 11, 101, and 102 mounted on the main cam shaft 10 0f the machine. One or the other of two followers 14, 14 (see FIG. 5) can be brought into engagement with the cams. In order to transmit the movement imparted to the roller followers 14 or 14' engaging one of the cams, use is made of a follower lever fixed on the shaft 12, including an arm 13 extending downward from the shaft and an arm 18 extending upward from the shaft. A coupling arm 15 connects the upper end of the upper lever arm 18 to the machine needle bar 35. The cam 11 serves for producing normal knitting movements for loop formation. The cam 101 serves for producing the movement of the machine needle bar for transfer of the machine needle loops onto the frame needles 40 on changing over from plain or Jersey material to rib material. In order to take up the initial course the further disc cam 102 is provided. For enabling the follower lever 13 to be actuated by any one of the three cams 11, 102 (with raised portion 102), and 101 arranged side by side, each of the two roller followers 14 and 14' can be shifted by means of a follower shifter fork 16 on follower carrying pin 140. The shifting movements are shown by double arrows in FIG. 5. A tension spring serves for pressing that roller follower which is in the operative position in engagement with the cooperating cam for operating the machine needle bar.

A further means for guiding movement of the machine needle bar 3 is constituted by a support lever 180 which is pivoted to the machine needle bar 3 and has its lower end journalled on a shaft 183. Swinging of the support lever 180 about the shaft 183 causes the machine needle bar 3 to move with a vertical component as is required for pressing the bearded needles 35.

For producing welt the machine needle bar 3 can be arranged to be actuated by resilient draw otf means. The draw off means as used in the embodiment of FIG. 1 is shown in detail in FIG. 6. It comprises compression springs 153 which are mounted in sleeves forming parts of the coupling arms 15. Each spring abuts at one end against the end of the sleeve 150 of the respective coupling arm 15 while the other spring end abuts against an annular fiange 154 on the portion of a pull rod 151 extending into sleeve 150. As a result each pull rod 151 is subjected to a resilient force which tends to telescope or retract it into the sleeve 150. The end of the sleeve opposite pull rod 151 is pivoted to a lever 18 while the pull rod is rigidly connected with the machine needle bar 3.

In order to be able to use the coupling arms 15 both as rigid connecting links for transmission of knitting movements, and also as resilient element for fabric draw off, a locking mechanism is provided. This mechanism includes a control projection in the form of a short rod 152 projecting laterally from pull rod 151 and slidable in an L-shaped slot 155 (with circumferential part 155' and axial part 155") in the sleeve 150. The inner end of control rod 152 is fixed in a further sleeve 156 journalled on pull rod 151 and fitting between the annular flange 154 on rod 151 already mentioned and a second annular flange 157 on the pull rod 151.

In order to transmit knitting, that is to say loop-forming movements, the control rod 152 is moved in the manner of a door bolt, first axially along slot part 155" and then circumferentially into the part 155 of the slot, a counterclockwise swinging of control rod 152 being necessary to accomplish such movement. As a result relative axial movement between the sleeve 150 and the pull rod 151 is prevented. In order to unlock the resilient means, so that the resilient force of spring 153 can be used for fabric draw off, the locking or central rod 152 is moved into the axial part 155" of the slot 155 by rotating it in a clockwise direction so that the control rod 152 is released enabling relative axial movement between the sleeve 150 and the pull rod 151 to take place along a distance equal to the length of the part 155 of the slot 155.

The knock over bar 5, which is caused by a tension spring 58 to abut against the machine needle 35, is caused to move horizontally in conventional manner by means of a two-armed lever 112, which is pivoted on the shaft 111, and is equipped with roller followers 113, 113 for cooperation with two adjacent cams 110 and 115 fixed on the main cam shaft 10. The disc cam 110 serves for moving the knock over bar during the production of rib material while the disc cam 115 serves for drawing back the knock over bar out of the working position. An abutment 117 which is pivoted on shaft 116 serves for opposing the action of a tension spring 118 and thus holding the lever 112 so that there is no engagement with the cam 115 and consequently no reciprocation of knock over bar 5 such as during the production of rib material. In order to enable the lever 112 to respond to either one or the other of the two cams 110 and 115, the two roller followers 113 and 113' can be shifted by means of a shifting fork 161 on the follower shaft 114 in an axial direction.

For the production of rib material the roller follower 14' is in engagement with the disc cam 11 and its resulting movements are transmitted to the levers 13, 18 and the coupling arm 15 the rod 152 of which is locked in slot portion 155 so as to make the coupling arm rigid. As a result there is on cenventional transmission of movement to the machine needle bar. The knock over bar 5 is also moved in a conventional manner by the lever 112 which is moved by the roller follower 113' and the disc cam 110.

If plain or Jersey fabric is to be produced following a rib border in which the machine needle bar has been moved by the cam 11, corresponding to the follower 14 in its left-hand position as shown in FIG. 5, the machine needle stitches are transferred to the corresponding frame needle 40 by shifting the roller follower 14' and bringing it into engagement with the stitch transfer cam 101. This is carried out when the recess 102" in cam 102 is opposite roller follower 14' in its left-hand position in accordance with FIG. 5. Owing to the engagement of the roller follower 14 with cam 11 the roller follower 14' can be moved through the recess 102" and onto the disc cam 101. When, on further rotation of the cams the roller follower 14' comes onto the projection 101' of cam 101 and roller follower 14 is consequently brought out of engagement with cam 11, the follower 14 is moved to the right as seen in FIG. 5, so as to be out of engagement with cam 11. After transfer of the stitches from the machine needles onto the frame needles by cooperation of follower 14' with cam 101, the machine needle bar 3 is retracted into an inactive position. This happens when follower 14 has reached a recess part 101" in cam 101 aligned with the recess 102" in cam 102. This recess 101" is so deep that the lever 13 moves so far to the right under the action of spring 130 that an abutment 131 on the lower end of the lever comes into contact with an abutment 19. As a result follower 14' ceases to make contact with the cam 101. It is then shogged into its left-hand position as shown in FIG. 5. Instead of using the abutment 19 it is possible to vary the construction and provide a concentric disc for cooperation with roller follower 14.

For knitting a welt the machine needle bar 3 is responsible for holding, drawing, and transferring the initial course. The rigid connection between the pull rod 151 and the sleeve 150 of the coupling arm 15 is discontinued by moving rod 152 circumferentially into the axial portion 155" of slot 155. As a result when the lever 18 is retracted away from the frame needles 40 the spring 153 transmit a resilient pulling force to needle bar 3. Roller follower 14 cooperates with cam 102 and moves the machine needles forwards towards the frame needles for production of the initial course which is made using both the frame and the machine needles. When the initial course has been completed, the roller follower 14 is moved into its left-hand position as shown in FIG. 5 so that no further knitting movements are transmitted to the machine needle bar and the lever 13 is arrested by abutment 19. The spring 153 only exerts a steady force on the machine needle bar 3 so that further welt courses knitted by the frame needles 40 are held under tension and drawn off. In other words the spring 15.3 causes the machine needle bar 3 to perform a draw off movement while allowing for the knitting movements of the frame needles 40.

The draw off travel of the machine needle bar is determined by the setting of the abutment 19. Preferably draw off is continued until the machine needles 35 have moved so far away from the knitting zone of the frame needles 40 that a welt rod 60 can be placed by means of a rod holder 6 on the drawn off fabric and laid in the draw off hooks 450. The hooks then continue draw off of the fabric and hold it taut until the desired number of courses for the welt has been reached. For closing the welt, the locking rods 152 are moved back into the circumferential slot parts so that the resilient action of the spring is arrested and the coupling arms 15 again establishes the rigid connection between the machine needle bar 3 and the lever 13, 18. In accordance with the stitch transfer system used by the knitting machine, the machine needle bar 3 is shifted by the rail 36 which moves the fingers 360. Also at a position opposite the cam recess 102" the follower 14 is shifted by follower shifting fork 16 onto the cam 101 and the roller follower 14 brings the machine needle bar 3 from the rest position into the transfer position for closing the welt. The loops or stitches of the initial course are then transferred with the help of stitch opening elements or the like onto the frame needles 40 in a conventional manner. The machine needle bed 3 is then shifted back into its initial position by means of the rail 36.

In accordance with whether a rib fabric or a plain fabric is to be produced, the machine needle bar 3 is operated by means of the cam 11, or after being moved back by cam 101, the roller follower 14' is moved into its left-hand position in accordance with FIG. 5 so that the lever 13 is left supported by abutment 19.

While, in accordance with the above description, during the production of plain fabric by means of the frame needles 40 only the machine needle bar is made inactive, it is also convenient to bring the knock over bar 5 into a rest position by releasing the roller follower 113 from its cams by means of the abutment 117, as has already been described above. In the case of a long draw off travel of the machine needle bar, this inactivation of the knock over bar 5 is necessary.

FIG. 2 shows a further embodiment of the invention in which for the draw off movement of the machine needle bar 3 with edge 34 guides 2 are provided. Each guide 2 has one end journalled on a shaft 132 fixed in the machine frame, while the other ends of the two guides are supported by a lifting rod 181 which is used to swing the guides 2 upwards in order to impart a pressing movement to the machine bearded needles 35. If latch, pipe or compound needles are used as machine needles, no pressing movement of the machine needles 30 will be required. In this case the guides 2 will be fixed in the machine frame and will be supported by a holding means (as will be described with reference to FIG. 3) though the other ends of the guides can still be supported on shaft 132. The shaft 132 can be used to shift the guides 2 and machine needle bar 3 when necessary for the stitch transfer system used by the knitting machine. Preferably the machine needle bar 2 runs in the guides 2 on rotary pins 32 which are carried in ball bearings, though it is also possible to use other suitable means for mounting the needle bar, such as sliding means. The machine needle bar and the lever arm 18 are connected by tension springs 158. The coupling arms have horizontally elongated openings 196 into which pins 133 fit for connecting the coupling arms 195 with lever 18. If locking pins 197 are drawn upwards,

each pin 133 can move freely in the openings 196 without the coupling arms 195 being caused to move by the movement of the lever arm 18. Instead of a positive connection by means of pins 197, the tension springs 158 provide a resilient connection with the needle bar so that the needle bar is urged away from the frame needles to provide for draw off. The extent of draw off travel which can be reached depends on the displacement of the lever arm 18 and the length of the openings 196.

In order for the knock over bar and support part 51 to follow a draw off movement of the machine needle bar 3, there is a horizontally elongated opening 170 in the lever 17 for the connection with pin 53 connected with the knock over bar 5. A locking pin 17 1 is provided for locking the pin 53 in the opening 170. When the locking pin 171 is moved into its bottom position, the pin 53 can move freely; when it is raised such movement independently from the lever 17 becomes impossible. The spring 37 serves to hold the knock over bar 5 constantly in engagement with the machine needle bar 3 at its front edge 34. The manner of operation of this embodiment of the invention is similar to that shown in FIG. 1. Instead of using a welt rod 60 it is possible to use a welt bar 44 with welt needles 45 after half the courses required for the welt have been knitted. When half the welt has been knitted the welt needles 45 are inserted into the last course of loops carried by the frame needles 40. For this reason the draw off travel of the machine needle bar 3 can be adjusted to suit the required length in the Wale direction of the first half of the welt by means of an abutment 190 which is moved by means of a worm 191. The worms 191 for the several sections of the machine are connected together.

In the case of the embodiment of the invention shown in FIG. 3 an automatic coupling of the means for ensuring fabric draw off or knitting with the machine needles is provided. For this purpose the resilient means, that is to say the tension spring 137, used for bringing about fabric draw off is connected at one end with a projecting arm 136 on lever 134 while its other end is connected with projecting arm 135 on lever 127 carrying the roller followers 14 and 14'. The lever 134 and the lever 127 are swingable about the axis of shaft 12. One lever is fixed to the shaft while the other is journalled on it and the two levers are connected together by means of an electrically operated magnetic coupling 120 so that the levers can either be freely moved in relation to each other about the axis of the shaft 12 or are rigidly connected together. If they are freed to move in relation to each other, the tension spring 137 tends to pull arms 135 and 136 together. This means that, when the coupling 120 is out of action, the draw off force will be applied via coupling arms 121 and coupling parts or pins 33 to the machine needle bar 3 substantially irrespective of the position or movement of the lever 127. The drive mechanism for the knock over bar 5 is similar so that in the case of a long draw off travel the knock over bar 5 can be retracted together with the machine needle bar 3.

The levers 172 and 173 have projecting arms 174 and 175, respectively, connected by a tension spring 176. Furthermore there is a coupling 177 which connects the lever 172 with the lever 173 via shaft 111. If a welt is to be produced, couplings 120 and 177 are inactivated. As a result the knock over bar 5 is acted upon by the spring 176 so that its front part 51 is pressed on the front edge 34 of the machine needle bar 3. The bar is thus acted upon in the draw off direction by the tension springs 137 and 176 so that it draws off and holds taut the fabric produced. By shifting the roller follower 14 the lever 127 is moved so that its abutment 131 comes to rest against abutment 190 which is set to half the length of the welt length in the wale direction. The abutment 138 of the lever 127 thus comes out of contact 8 with the arm 136 since the lever 134 is prevented by the row of loops of the welt on the machine needles from following this movement immediately.

Simultaneously with the shifting of the roller follower 14 the shifting fork 162 causes the roller follower 113 for the knock over bar to move onto the cam or disc 119 with a circular periphery. This causes the tension spring 176 to be extended so that the knock over bar 5 which lies against the front edge 34 of the machine needle bar 3 moves with the machine needle bar 3 during the whole of its draw off travel. When the number of courses necessary for half the Welt fabric is completed, the arm 136 of the lever comes to rest against abutment 138 and the couplings 120 and 177 are activated so as to make a rigid connection between the levers 127 and 134, on the one hand, and between the levers 172 and 173 on the other hand. At the same time as the couplings are activated, the Welt bar 44 is brought into action so that the course of loops still on the frame needles 40 is impaled on the welt needles and the second half of the welt is knitted and drawn off. For bringing the welt bar 44 into operation a limit switch 139 may be mounted on abutment 138. When the full number of courses necessary for the welt has been knitted, the machine needle bar 3 and the knock over bar 5 are moved into their working or transfer position respectively by shifting the roller followers 14' and 113.

In the embodiments of the invention described, draw off of the machine needle bar 3 is carried out in a most simple manner using an elastic element which can be locked or put into operation by means of a coupling means. However, it is also possible to use other means for imparting the draw off movement to the machine needle bar 3 as may be convenient in a straight bar knitting machine. FIG. 4 shows for example a construction with draw off mechanism without a resilient element, the draw off force being capable of being adjusted to suit the width of the material. The means providing the draw off force shown in FIG. 4 comprise a torque motor 47, that is to say a motor designed to produce a certain torque irrespective of whether it is allowed to rotate or not. The motor is connected with a pinion 471 which cooperates with a rack 470. The rack is coupled with the lever 123. The movement of the rack 470, which is carried in two bearings 23 and 230, is linked with the lever 123 by means of a sliding block 125 fitting in a slot 124 in the lever 123.

For the draw olf movement of the machine needle bar the torque motor 47 is switched on simultaneously with the inactivation of the couplings and 177 which, like the torque motor are powered via electrical leads which are shown in the drawings but not especially referenced. The lever 123 has an abutment 126 which is arranged to actuate a limit switch 139 when half the number of courses required for the welt have been produced. When the switch is actuated, the torque motor 47 is inactivated and simultaneously the rigid connection between the levers 127 and 172 on the one hand, and the levers 123 and 173 on the other restored.

In the arrangement in accordance with FIGS 3 and 4 the machine needle bar 3 is connected by means of coupling arms 121 with the levers 134 and 123 respectively and also carried in guides 20. The design is such as to permit easy removal of the machine needle bar 3.

For this purpose the coupling arms 121 have open fork-shaped parts 128 which in the operational condition fit over pins 33 and drive the needle bar 3. Engagement of the parts 128 with the pins 33 is ensured by means of tension springs shown in FIG. 3 connecting the coupling arms 121 with the levers 134 and 123. However, instead of using such springs to bring about engagement, it is also possible to use fork-shaped parts 128 with suitable projections for holding onto the pins 33.

This case of removal of the needle bar 3 is of substantial importance when it is desired to use the machine with h a different needle set out. The arrangements shown are substantially better than arrangements which allow change of the needle set out by retracting selected needles without changing the machine needle bar.

Normally for the production of a rib border followed by plain or Jersey material the machine needle bar 3 has half as many needles as the frame needle bar 4 (as shown in FIG. 7). If a welt is also produced with this needle set out, an initial course of the welt is only trans ferred with every second loop, as is the case for example with seamless stockings on circular knitting machines. If, however, a welt is desired which is transferred with every loop, the machine needle bar 3 is exchanged for a machine needle bar which has the same number of needles as the frame needle bar 4 (see FIG. 8). If, however, it is desired to produce a rib border with 2:2 set out, the machine needle bar can be readily exchanged for one with a 2:2 needle set out, as shown in FIG. 9.

What is claimed is:

1;. In a straight bar knitting machine, a frame needle bar having vertical needles, first cam means, first linkage means operatively connecting said frame needle bar with said first cam means for actuating said frame needle bar to perform knitting movements, a machine needle bar having horizontal needles, second cam means, and second linkage means for operatively connecting the machine needle bar with the second cam means for actuating the machine needle bar to perform knitting movements, the improvement comprising force-producing means for exerting a welt draw-otf force on the machine needle bar, and control means for selectively disrupting the connection between the second cam means and the machine needle bar through the second linkage means for interrupting rib-knitting movement of the machine needle bar and operatively connecting said force-producing means with the second linkage means to exert a draw off force on the machine needle bar for knitting plain fabric, and for subsequently inactivating the force-exerting connection between said force-producing means and the machine needle bar through the second linkage means and restoring the operative connection between the second cam means and the machine needle bar through the second linkage means to resume knitting actuation of the machine needle bar for knitting rib fabric.

2. In the machine in accordance with claim I, a knockover bar, third cam means, third linkage means for operatively connecting said knock-over bar and said third cam means for actuating said knock-over bar to perform working movements, and means for selectively operatively disconnecting said third cam means from said knock-over bar through said third linkage means and keeping said knock-over bar in its inoperative position when the second cam means is operatively disconnected from the machine needle bar through the second linkage means, or for operatively connecting said third cam means with said knock-over bar through said third linkage means when the second cam means is operatively connected to the machine needle bar through the second linkage means.

3. In the machine in accordance with claim 1, the force-producing means including a resilient element changeable in dimension when unrestrained, and the control means including a linkage element operable to prevent dimensional change of said resilient element and to transmit knitting movements from the second cam means to the machine needle bar through the second linkage means.

4. In the machine in accordance with claim I, the second linkage means including a lever arm and telescoping means connected between said lever arm and the machine needle bar, the force-producing means being operatively connected to said telescoping means for urging said telescoping means in one direction, and the control means being operatively connected to the telescoping Id means for selectively restraining telescoping movement of said telescoping means under force exerted thereon by the force-producing means for transmitting knitting movements of the second cam means through the second linkage means to the machine needle bar, and for freeing said telescoping means to move telescopically.

5. In the machine in accordance with claim 1, the second linkage means including an upwardly extending lever having an arm projecting laterally therefrom, a downwardly extending lever having an arm projecting laterally therefrom and means mounting said two levers for swinging relative to each other about a common axis, the force-producing means including resilient means operatively connecting said two arms and exerting force thereon tending to swing said levers relative to each other, and the control means is operatively connected to said two levers to restrain relative movement thereof by selective operation of the control means.

6. In the machine in accordance with claim 1, an abutment engageable by the second linkage means for limiting travel of the machine needle bar for welt draw-off when the second cam means is not operatively connected to the machine needle bar through the second linkage means.

7. In the machine in accordance with claim 1, the second linkage means including a swingable drive lever and coupling means connected to said drive lever and engageable with portions of the machine needle bar, said coupling means being swingable out of its position in which it is engageable by the machine needle bar.

8. In the machine in accordance with claim 1, guide means guiding the machine needle bar during welt drawoff movement thereof while the second cam means is not operatively connected to the machine needle bar through the second linkage means.

9. In the machine in accordance with claim 8, a frame for the knitting machine carrying the guide means in fixed relationship thereto.

10. In the machine in accordance with claim 8, rollers carried by the machine needle bar and engageable with the guide means for supporting the machine needle bar, and roller bearings mounting said rollers.

11. In the machine in accordance with claim 1, a lever carrying the machine needle bar, and means mounting said lever for swinging to guide the machine needle bar for vertical movement in addition to being movable horizontally to effect horizontal knitting or welt draw-off operations.

12. A straight bar knitting machine comprising a bar having vertical frame needles, first cam-operated means for operating said frame needles to knit, a bar having horizontal machine needles, second cam-operated means for operating said machine needles to knit, control means operable to render said second cam-operated means inoperative to effect knitting operation of said machine needles, and means for exerting a welt draw-off force on said bar of horizontal machine needles when, by operation of said control means, said second cam-operated means have been rendered incapable of effecting knitting operation of said machine needles.

13. The machine in accordance with claim 12, a knockover bar, drive means for producing working movement of said knock-over bar in accordance with knitting movement of the bar of horizontal machine needles, means for disengaging said knock-over bar from said drive means when the second cam-operated means have been rendered incapable of effecting knitting operation of the machine needles, and means for withdrawing said knockover bar in accordance with the drawing-off of the bar of horizontal machine needles.

14. The mechanism in accordance with claim 12, the draw-off force means including resilient means, and means for activating said resilient means when the second cam-operated means have been rendered incapable of effecting knitting operations of the machines needles.

15. The machine in accordance with claim 14, the means for activating the resilient means being optionally operable to restrain deformation of the resilient means and to effect a rigid connection between the second camoperated means and the bar of horizontal machine needles for effecting knitting operation of the machine needles.

16. The machine in accordance with claim 12, the means for exerting a welt draw-off force including at least one arm resiliently variable in effective length and having spaced portions thereof connected to the second cam-operated means and to the bar of horizontal machine needles, respectively, for effecting knitting operation of the machine needles, and locking means operable at will for preventing changes in the length of said arm.

17. The machine in accordance with claim 16, in which the arm includes a sleeve having an L-shaped slot in the wall thereof with one leg extending axially and the other leg extending circumferentially, a pull rod extending into said sleeve and normally movable lengthwise relative thereto and a control rod projecting laterally from said pull rod through said sleeve slot, said control rod being movable along said slot in the manner of a door bolt first axially and then circumferentially for locking said pull rod against lengthwise movement relative to said sleeve.

References Cited UNITED STATES PATENTS 654,982 7/1900 Hurley et al. 6688 774,464 11/1904 Barratt 6688 2,898,753 8/1959 Bauer et al. 6696 3,386,269 6/1968 Pynegar et al. 6690 X 3,401,538 9/1968 Start et al. 6696 X RONALD FELDBAUM, Primary Examiner 

